Aim: To investigate the effects of 2-amino-5-phosphonovalerate-pharmacology (AP-V) and bicuculline on somatostatin (SST)-positive neurons in hypothalamus of rats subjected to acute hypobaric hypoxia.
Methods: SST-immunoreactivity (IR) and somatostatin mRNA (SS mRNA)-positive neurons were measured by immunohistochemistry and in situ hybridization methods.
Results: Compared with control rats, SST-IR and SS mRNA-positive neurons in hypothalamic periventricular nucleus (PeV), paraventricular nucleus (PVN), and arcuate nucleus (ARC) increased after acute hypobaric hypoxia for 6 h (P < 0.01), and these effects were markedly inhibited by AP-V (10 microg, icv), a highly selective N-methyl-D-aspartate (NMDA) receptor antagonist, whereas were strongly enhanced by bicuculline (1.5 mg/kg, ip), a gamma-aminobutyric acid (GABAA) receptor antagonist.
Conclusion: SST possibly participates in acute hypoxic reaction in hypothalamus, furthermore, glutamate and GABA can affect somatostatin release and synthesis in hypothalamus through NMDA and GABAA receptors respectively.